Transformer



June 2 7' R. T. ST. JAMES TRANSFORMER Filed April 12. 1924 M I y Patented June 21, 1927.

' humidity in the UNITED STATES PATENT OFFICE.

ItOBEBT '1. ST. JAMES, OF CHICAGO, ILLINOIS.

TRANSFORMER.

Application filed April 12, 1924. Serial No. 705,966.

This invention relates to improvements in transformers and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The primary object of the invention is to provide a small, compact and highly efiicient transformer especially adapted for use in super audio frequency circuits.

A further object of the invention is to provide a transformer of the kind which is so constructed that identical uniformity of inductances and electrical constants is insured in the making thereof.

Another objectof the invention is to provide a transformer of the kind which is not subject to variations due to the changes of surrounding atmosphere.

These objects of the invention as well as the many advantages thereof will more fully appear as I proceed with my specification.

' In the drawings Figure, 1 is a perspective view of a transformer embodying my invention;

Figure 2 is a vertical sectional view through the same, on an enlarged scale;

Figure 3 is a diagrammatic view showing the wiring of my improved transformer.

Referring now in detail to that embodiment of the invention illustrated in the accompanying drawings :5 indicates bin or spool upon which the primary an secondary coils 6 and 7 respectively of the transformer are wound. Said bobbin is preferably made of 'a dielectric material in the form of a tubular body 8 with top, intermediate and bottom radial flanges 9, 10 and 11 respectively. ing of the primary coil, which is wound a suitable number of turns about the tubular body of the bobbin between the flanges 9 and 10, and 13 indicates the wiring of the secondary coil which is wound a suitable number of turns about the tubular body of the bobbin between the flanges 10 and 11 thereof. The Wiring of course is of the insulation covered type.

The bobbin with the windings thereon is preferably enclosed in a sealed bulb 14, which is made of glass having a lead content which shields the windings trom external capacity. The bottom end 15 of the bulb is made of a reduced diameter and is secured in a base or socket '16 of the moulded dielectric type by means of a.v cemcntitious material 1?. The base or socket 16 is provided at the bottom end with a base flange 18 :1. bobd' "a small condenser 27 upon the bobbin 5.

12 indicates the wir which includes a plurality of radial bosses 19. Each boss is cored out on its under side as shown in Fig. 2. In each boss is anchored a screw 20 upon which is threaded a nut 21, said screws and nuts providing the binding posts or terminals for the current conductors from the primary and secondary coils 6 and 7. The base flange 18 also includes diametrically opposite, apertured bosses or ears 22 for the passage or screws to securely fix the base upon a support. I

The bulb 14; includes at its bottom end, a centrally disposed upright tubular post or stem 23 which is connected at its bottom end to the bottom end 15 of the bulb, and is sealed in the usual manner at its top end. Said post 23 has a shouldered tubular extension 24 at its top end which extends into the bottom end of the bore of the bobbin 5, so that the bobbin is supported by said post in a manner holding it cent-rally within the bulb. The top end of the bulb is made hemispherical and has a depending tubular member 25 which extends into the top end of the bore of the bobbin 5 and assists in holding the bobbin in position in the bulb. The tubular member 25 is made in alignment with the sealing nib 26 at the.top end of the bulb 14:.

Preferably but not necessarily so, I mount Said condenser is of the fixed capacity type and may be made up of alternating laminae of mica and foil, but as the details of construction of the condenser form no part of the present invention, it has not been illustrated nor will it be described more in detail here. The condenser is interposed between thetop and intermediate flanges 9 and 10 of the bobbin and is spaced a short distance outwardly from the coil windings 12 thereon.

The terminals 12"---12 of the primary coil 12 and the terminals 13-13" of the secondary coil pass down through and are sealed in the head of the stem 23, and be low the same are inclosed in small rubber or like insulation tubings 28 and are con-- 1313" respectively, have been sealed in the top end of the post, the top end of the tubular member is connected to an exhaust manifold of a pumping apparatus in the manner well known. Preferably a pumping apparatus which includes dehydrating means is used. The bulb is dehydrated and exhausted by the apparatus until the bobbin windings and condenser are thoroughly dehydrated. The bulb may be sealed at this stage if desired, the pressure or absence of pressure being immaterial so long as the dehydration of the elements within the bulb has reached the desired limit and this limit is maintained.

Instead of air under pressure within the bulb, certain gases maybe employed. I11 any case it is essential that all the elements enclosed in the bulb be dehydrated and this condition be fixed or maintained within the bulb by sealing itfrom atmospheric pressure, preferably by collapsing the nib 26.

ransformers embodying my invention and made as above described have many advantages. Maximum uniformity in the electrical constants of the coils or windings of the transformers is insured. Thus when a plurality of my improved transformers are used as inter-stage units in a particular circuit, a matching or standardization of said units is insured. The desired uniformity of the inductance values of the transformers made as mentioned, may be indeed closely adhered to.

With a vacuum existing in the bulb, one

advantage is attained :An increased intercoil action is attained because of the greater permeability of the lines of force in vacuum over air at atmospheric pressure.

With the glass of the bulb containing a large percentage of lead, the coil windings are shielded or protected from external capacity.

\Vhile in describing my invention I have referred to certain details of construction as well as arrangement of parts and pressures and absence of pressures, I do not wish to be limited thereto except as may be pointed out in the appended claim.

I claim as my invention: V

A transformer comprising. a sealed vessel having centrally disposed standard including a tubular extension, a tubular bobbin having a centrally disposed bore mounted 011 said standard with said extension projecting into one end of said bore. said vessel including an opposed tubular extension which projects into the other end of said bore, a base on which said vessel is mounted which base includes binding posts primary and secondary windings on said bobbin and conductors leading from said windings and sealed in and passing through said standard and connected to said binding posts, said bobbin and windings together with the interior of said vessel being dehydrated.

In testimony that I claim the foregoing as my invention, I affix my signature this 9th day of April, 1924.

ROBERT T. ST. JAMES. 

